Sentences can be divided into parts called clauses. A relative clause is a part of a sentence that describes the person or thing we are talking about and is connected to other clauses in the sentence via a relative pronoun
The woman that has just left the shop didn't buy anything.
( ' that has just left the shop ' modifies the noun ' woman ' by telling us which woman the speaker is referring to)
That, Who, Which, Whose can be used to introduce clauses in sentences:
The woman who interviewed me was very friendly.
I can't stand dogs that bark loudly.
It gives essential information about the noun or noun phrase it modifies, without which the sentence wouldn't make sense as the listener or reader would not be able to identify the noun in the sentence:
The hotel that we stayed in wasn't bad .
( 'that we stayed in' tells the listener which hotel we are talking about; it defines the hotel)
'Who', 'whose' and 'that' can be used for people.
'Which' 'whose' and 'that' can be used for things
It gives extra information about the noun or noun phrase and has commas at both ends.
The commas have a similar function to brackets.
My sister, who lives in France , is coming to stay with me next week.
My sister ( she lives in france) is coming,…
( 'who lives in France' is not essential, which means that I only have one sister )
'Who' and 'whose' are used for people.
'Which' and 'whose' are used for things.
'That' cannot be used in a non-defining relative clause.
1 . He gave me the letter.
The letter was in a blue envelope.
He gave me the letter, which was in a blue envelope.
2. He gave me the letter.
I read the letter immediately.
He gave me the letter, which I read immediately
3 . My aunt came from the North of England.
She is dead now.
My aunt, who is dead now , came from the North of England
4. She’s studying English.
Many people hate English.
She’s studying English, which many people hate .
5. I’ve just met Susan.
Susan’s husband works in London.
I’ve just met Susan, whose husband works in London .
6. John’s mother has six grandchildren.
She lives in Scotland.
John's mother, who lives in Scotland, has 6 grandchildren.
7. Elephants are very unusual.
Elephants love mice.
Elephants that love mice are very unusual .
(This tells us which elephants we are talking about).
8. Elephant can sometimes be found in zoos.
Elephants are large and grey.
Elephants, which are large and grey, can sometimes be found in zoos .
(This gives us some extra information about elephants - we are talking about all elephants, not just one type or group).
9. My friend John has just written a best-selling novel.
He went to the same school as me.
My friend John, who went to the same school as me, has just written a best-selling novel.